He knocks on the door and an old man answers. The guy says "I saw the sign for the talking dog for sale". The old man says "Yep, he's out back".

They walk around to the back and the old man leads the guy to the fenced in area where the dog is sleeping.

The guy asks, "He really talks, huh?" The old man bangs on the fence and screams "Wake up idiot, someone's here to see ya". The dog wakes up and walks over to them and sees the guy standing there. The dog says "Hey there, how are yah?" The guy is shocked and says "You can really talk! How the hell is that possible?" The dog says "Well when I was born the government put a chip in my brain to make me smarter and give me the ability to talk. They used me for many covert operations all over the world. I helped take down some of the worst criminals ever. I even helped take down Sadam Hussein".

The guy is stunned. He says to the old man "This dog is amazing! How could you sell him for 10 bucks?"